Three dimensional thin film devices and methods of fabrication

Abstract

Methods for making thin film multiple layered three-dimensional devices using two-dimensional MEMS techniques for use in a variety of applications including endovascular, endolumenal, intracranial, and intraocular medical applications. In the general method, a thin film first layer of the device material is deposited over a release layer which in turn is deposited on a substrate. An other release layer is deposited on the first device layer, with portions of the other release layer removed, leaving a pattern in the first device layer. In a similar manner a second layer of device material is formed in a pattern overlying the first device layer with portions of the two layers joined together leaving a portion of the release layer between them. The two release layers are removed and the first and second layers of the device material are formed into a three-dimensional shape suitable for the desired end-use application.

What is claimed is:  
     
       1. A method of fabricating an article for use in shaping a three dimensional thin film device comprising the steps of providing first and second thin film device layers, the device layers each being formed of a device material selected from the group consisting of a device material which is of the same type of material for both layers, and a device material for the first layer which is of a different type of material from the device material for the second layer, the first and second layers each having first and second portions, joining the first portions of the layers together, providing a sacrificial layer between the second portions, removing the sacrificial layer leaving a space between the second portions, and plastically deforming at least one of the first and second device layers sufficient to change the size of the space. 
     
     
       2. A method as in  claim 1  in which the steps of providing the device layers are carried out by depositing a first release layer of a material on a substrate, depositing the first device layer on the first release layer, depositing a second release layer of a material on the first device layer, removing a portion of the second release layer leaving a pattern which comprises an other portion which remains of the second release layer that does not cover the first portion of the first device layer, and depositing the second device layer on the other portion and the first portion of the first device layer. 
     
     
       3. A method as in  claim 2  in which the step of joining is carried out by the causing the first portion of the second device layer to join with the first portion of the first device layer during the step of depositing the second device layer. 
     
     
       4. A method as in  claim 2  including the step of forming the second release layer of a material selected from the group consisting of Cr, Al, Ag, Au, TiCuAg and TiCuAgCr, polyimide and a photoresist. 
     
     
       5. A method as in  claim 1  and further comprising the step of deforming at least one of the device layers in a direction which enlarges the space. 
     
     
       6. A method of fabricating an article for use in shaping a three dimensional thin film device comprising the steps of providing a thin film base layer, providing a thin film second layer, the base and second layers each being formed of a device material selected from the group consisting of a device material which is of the same type of material for both layers, and a device material for the base which is of a different type of material from the device material for the second layer, the base and second layers each having first and second portions, joining the first portions of the layers together, providing a space between the second portions, deforming at least one of the layers into a three dimensional shape, and the step of deforming the one layer is carried out by inserting a mandrel sufficiently far into the space to spread the second portions of the layers apart. 
     
     
       7. A method of fabricating an article for use in shaping a three dimensional thin film device comprising the steps of providing a thin film base layer, providing a thin film second layer, the base and second layers each being formed of a device material selected from the group consisting of a device material which is of the same type of material for both layers, and a device material for the base which is of a different type of material from the device material for the second layer, the base and second layers each having first and second portions, joining the first portions of the layers together, providing a space between the second portions, and the step of deforming the one layer is carried out by inserting a mandrel of a desired shape into the space with a force which is sufficient to deform the one layer into a shape which is commensurate with the desired shape. 
     
     
       8. A method as in  claim 1  in which the steps of providing the first and second device layers are carried out by sputter depositing the materials of the device layers. 
     
     
       9. A method as in  claim 1  in which the steps of providing the first and second device layers are carried out by forming the device material of a shape memory alloy. 
     
     
       10. A method as in  claim 1  and further comprising the step of forming fenestrations in at least one of the first and second device layers. 
     
     
       11. A method of fabricating an article for use in shaping a three dimensional thin film device comprising the steps of providing a thin film base layer, providing a thin film second layer, the base and second layers each being formed of a device material selected from the group consisting of a device material which is of the same type of material for both layers, and a device material for the base which is of a different type of material form the device material for the second layer, the base and second layers each having first and second portions, joining the first portions of the layers together, providing a space between the second portions, the steps of providing the base and second layers are carried out by depositing a first release layer of a material on a substrate, depositing the base layer on the first release layer, depositing a second release layer of a material on the base layer, removing a portion of the second release layer leaving a pattern which comprises another portion which remains of the second release layer that does not cover the first portion of the base layer, depositing the second base layer on the other portion and the first portion of the base layer, depositing a third release layer on the second base layer, removing a first portion of the third release layer leaving an other pattern comprising a second portion that remains of the third release layer, and depositing a third base layer of the device material on the first and second portions of the third release layer while causing a portion of the second base layer of the device material to join with a portion of the third base layer of device material which is not covered by the second portion of the third release layer. 
     
     
       12. A method as in  claim 1  comprising the steps of forming the first and second device layers into a planar form structure having a shape selected from the group consisting of polygonal and curvilinear. 
     
     
       13. A method as in  claim 12  which the polygonal shape is selected from the group consisting of triangular and rectangular. 
     
     
       14. A method as in  claim 12  which the curvilinear shape is selected from the group consisting of semicircular and circular. 
     
     
       15. A method of fabricating an article for use in shaping a three dimensional thin film device comprising the steps of providing a thin film base layer, providing a thin film second layer, the base and second layers each being formed of a device material selected from the group consisting of a device material which is of the same type of material for both layers, and a device material for the base which is of a different type of material from the device material for the second layer, the base and second layers each having first and second portions, joining the first portions of the layers together, providing a space between the second portions, forming a plurality of fenestrations through at least one layer while positioning the fenestrations in a plurality of transversely spaced apart rows and with the fenestrations in each row being longitudinally spaced a first distance apart and further with the fenestrations in one row being longitudinal offset a second distance from the fenestrations in the rows adjacent to the one row, the first and second distances being sufficient to enable deformation of the one layer into a three dimensionally curved shape. 
     
     
       16. A method as in  claim 15  and further including the step of deforming the one layer into a three dimensionally curved shape. 
     
     
       17. A method as in  claim 16  and in which the deforming step is carried out by deforming the one layer into at least a portion of a shape selected from the group consisting of a sphere and a spheroid. 
     
     
       18. A method as in  claim 15  in which the forming step is carried out by forming the fenestrations into slot shapes. 
     
     
       19. A method of fabricating an article for use in shaping a three dimensional thin film device comprising the steps of providing first and second thin film device layers, the device layers each being formed of a device material selected from the group consisting of a device material which is of the same type of material for both layers, and a device material for the first layer which is of a different type of material from the device material for the second layer, the first and second layers each having first and second portions, joining the first portions of the layers together, providing a sacrificial layer between the second portions, and removing the sacrificial layer leaving a space between the second portions, providing the device material of at least one of the device layers to be a shape memory alloy, deforming the one device layer into a three-dimensional shape, and heating the one device layer at a temperature and time which are sufficient to cause the shape memory alloy to anneal while causing shape-setting of the one device layer into a memory shape which is commensurate with the three-dimensional shape. 
     
     
       20. A method as in  claim 6  and further comprising the steps of providing the device material of the one device layer to be a shape memory alloy, and heating the one device layer at a temperature and time which are sufficient to cause the shape memory alloy to anneal while causing shape-setting of the one device layer into a memory shape which is commensurate with the three-dimensional shape. 
     
     
       21. A method as in  claim 7  and further comprising the steps of providing the device material of the one device layer to be a shape memory alloy, and heating the one device layer at a temperature and time which are sufficient to cause the shape memory alloy to anneal while causing shape-setting of the one device layer into a memory shape which is commensurate with the three-dimensional shape.